I want to cahce responses from api (kind of calendar). They are rarely (never) changed, but become irrelevant with each passing day (no need to look into past).

What I considered:
- get monthly data and cache on client. Bad solution since every site visitor will still initiate request to api
- get monthly data and cache on server. Decent solution, but without server restarts this cache will pile up even if it is already outdated (month ended). As far as I found, there is no way to simply purge cache, only revalidate

Is there any better approach for this?

Ideal solution: cache month, erase cache on first day of next month.